WASHINGTON -- The leading contenders in the Democratic field for U.S. president have all pledged greenhouse gas emission cuts that would cost billions in the short term.

The plans would alter the way U.S. citizens power and heat their homes as well as fuel their vehicles but the candidates said the plans would save billions over the ensuing decades following the implementation of their plans, The Washington Post reported Tuesday.

Former Sen. John Edwards, D-N.C., said his plan to cut greenhouse gases by 80 percent from 1990s levels by 2050 would require sacrifice on the part of U.S. citizens.

"It won't be easy, but it is time for a president who asks Americans to be patriotic about something other than war," he said.

Democratic Party front-runner, Sen. Hillary Clinton, D-N.Y., said Monday her plan would require U.S. vehicles to average 55 miles per gallon by 2030. She said her administration would provide $20 billion in "Green Vehicle Bonds" to help the automotive industry conform to the standard.

"This is the biggest challenge we've faced in a generation -- a challenge to our economy, our security, our health and our planet. It's time for America to meet it," Clinton said in the Post report.